About a year and a half ago, I participated in a conference on the Iranian nuclear program and its wider aspirations in the Middle East. Among the participants were American, European, and Middle Eastern diplomats; a variety of foreign policy experts (many of whom previously worked at places like the State Department); a couple of journalists and activists; and a good variety military experts and former officers. At the end of the conference, we conducted a war exercise in which we simulated a US attack on Iran.
But before we got to this point, we had immediately dismissed the possibility of Israel carrying out the strike itself. Many of Iran's facilities are hardened and well-protected by anti-aircraft weaponry and a fleet of aging but capable aircraft that can at least harass any attack force. This isn't a problem for the US, since the USAF and USN have at their disposal highly advanced weaponry, from cruise missiles that can be accurately fired from relative safety to stealth B-2s and hundreds of other aircraft that can carry heavy ordinance and conduct repeated sorties.
But the IAF, while pound for pound arguably the world's best air force, does not have the aircraft and weaponry to carry out an attack that could substantially hamper or delay Iran's nuclear effort. It mainly flies retrofitted F-15s and F-16s that are extremely advanced but really only effective in high precision strikes. The problem is that there are too many Iranian facilities that are too far away (from Israel and from one another) and too well hardened for Israel to strike with effectiveness. In order to destroy Iran's most critical nuclear facilities (which are hardened and/or deep underground), multiple coordinated precision strikes on each facility with bunker busters will be needed. Israel has these bombs, but can't put enough of them on its available aircraft to repeatedly fly over a target and drop them with enough precision to destroy these facilities. They're further hampered by the fact that extra space on the wings to carry additional weaponry will be occupied instead by external fuel tanks. Israel will also only have one shot at this - it can't fly repeated sorties back and forth between Israel and Iran to conduct strikes. You then take into account Iran's (albeit modest and likely delayed) detection capabilities and its ability to at least attempt to thwart an attack, and it becomes highly unlikely that Israel could do much more than cause structural (but easily reparable) damage to Iran's facilities.
These aren't my opinions. They come from relatively senior Navy and Air Force officers who have conducted joint military exercises with Israel (and have in-depth knowledge of its military capabilities), as well people who have the diplomatic experience to fill in the rest of the gaps. People keep bringing up Osirak and the attack on the Syrian reactor as evidence that Israel can do this sort of thing with ease, but those strikes were a cake walk compared to what Israel will have to do to see similar results in Iran. And they both involved extremely sophisticated planning and execution. To me, it's pretty clear that Israel cannot initiate a strike against Iran, and Israeli policy planners surely know this. They're just keeping as quiet as possible about it in the hopes that the US decides to conduct the strike on its own.
Do you think that the Israeli political policymakers are fully aware that the IDF really doesn't think they could strike at Iran effectively? That is, do you think they were deceiving Goldberg, or are they deceiving themselves? The US invasion of Iraq illustrated to me that there is no real limit to the ability of politicians to believe that wishing will make it so in military affairs -- and no significant limit to the military willingness to go along, as long as the political leaders are ones the officer corps voted for.
I'm pretty confident that all of the Israeli policy makers that would be the ones making the decision on whether or not to attack Iran are fully aware of the IDF's limitations and know that a successful attack is not likely. Keep in mind that Netanyahu himself is a military man (coming both from a prominent military family and having served in the special forces) and has a deep respect for the military establishment. If they advise him that an attack is a very bad idea, he'll listen.
I don't necessarily think they're deceiving Goldberg (or themselves), but they're trying to get the message out that something really needs to be done about Iran. Before the Israeli attacks on Osirak and the Syrian reactor, all was quiet. No one had any idea that the Israeli's were behind the latter operation until maybe a month afterwards. Yet in the case of Iran, things are very different. Israel has engaged in multiple military exercises, has talked about the existential threat that Iran poses to its existence, and has threatened to attack Iran. This is not the sort of behavior that a country would engage in if they were preparing for what should be a very quiet, near-secret attack that their enemy wouldn't see coming. I believe all the saber rattling is an attempt to get the world community more involved in isolating Iran (with the hope of getting them to compromise on their program) or to try and force other players, namely the US, to destroy Iran's nuclear program by force.
One last thing: Be wary of comparing an Israeli attack on Iran to the US invasion of Iraq. Americans and our politicians are far more detached from the realities of war than Israelis are. For the US, the worst case scenario of a failed invasion of Iraq would have been military casualties, a prolonged conflict, and potential humiliation. Israel, however, has to cope with the realities of living in a dangerous neighborhood, with Hezbollah and Hamas posing a serious threat to the country's existence. Israelis will seriously weigh whether or not an attack is worth it knowing that its enemies on its immediate borders will be poised to strike.